Dupixent is used for eczema, COPD, and certain types of asthma. The most common side effects may include injection site reactions, pink eye, eyelid inflammation, cold sores, and mouth or throat pain.

Dupixent is a prescription medication that’s used in some cases to treat the following conditions in adults and certain children:

Dupixent is also used in adults to treat chronic obstructive pulmonary disease (COPD) with eosinophilia and a rare skin condition called prurigo nodularis.

Keep reading to learn about the common, mild, and serious side effects that Dupixent can cause.

Some people may experience mild or serious side effects during their Dupixent treatment. Examples of Dupixent’s more commonly reported side effects include:

For more information about some of these side effects, see the “Tips for managing side effects” section.

Examples of mild side effects that have been reported with Dupixent include:

  • injection site reactions
  • mild eye-related side effects
  • cold sores
  • joint pain
  • mouth or throat pain
  • toothache
  • difficulty sleeping
  • gastritis (inflammation in the stomach)
  • eosinophilia (increased numbers of white blood cells called eosinophils)

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. Do not stop using Dupixent unless your doctor recommends it.

For more information about some of these side effects, see the “Tips for managing side effects” section.

The list above doesn’t include all the side effects of Dupixent. For more information on the drug’s side effects, see the drug’s prescribing information.

The worst side effects of Dupixent reported in studies include:

  • serious eye-related side effects
  • eosinophilic conditions

For more information about these side effects, see the “Tips for managing side effects” section.

If you develop serious side effects during Dupixent treatment, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medication safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect during Dupixent treatment and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Allergic reaction

For some people, Dupixent can cause an allergic reaction.

In general, symptoms of an allergic reaction can be mild or serious.

What might help?

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue treatment with Dupixent.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Dupixent, they may have you switch to a different treatment.

Here are the answers to some frequently asked questions about Dupixent’s side effects.

Does Dupixent make you gain weight?

It’s possible. Weight gain wasn’t reported as a side effect in Dupixent clinical trials. However, other studies have looked at weight gain with dupilumab (Dupixent’s active ingredient).

One study found that weight gain was higher in people who received dupilumab than in people who took other systemic medications for atopic dermatitis. (Systemic means the whole body, rather than a medication applied to your skin.) A review of studies also suggests weight gain is a possible side effect of dupilumab.

In addition, weight gain is a common side effect of steroid medications taken by mouth. These are often used to treat severe eczema, asthma, COPD, and rhinosinusitis, which Dupixent also treats.

If you have concerns about weight gain with the medications you take, talk with your doctor. They can suggest ways to maintain a weight that’s right for you.

Can Dupixent cause hair loss?

No, Dupixent isn’t known to cause hair loss. This side effect wasn’t reported in studies of this medication. In fact, since it was approved for use, Dupixent has been studied to see if it can help with hair growth in people with alopecia areata.

Alopecia areata is a condition that causes hair to fall out in round patches. It can lead to total hair loss on the scalp or other parts of the body.

This condition occurs when a person’s immune system attacks their hair follicles by mistake. Dupixent works on an immune system protein that may be involved in alopecia areata.

How long do Dupixent’s side effects last?

Most mild side effects of Dupixent should get better on their own within a few days or a couple of weeks. But some may need treatment to help them clear up.

If you have side effects that last longer than a couple of weeks despite treatment, talk with your doctor.

Does Dupixent have long-term side effects?

Yes, some potential side effects of Dupixent may last a long time. Exactly how long side effects last will depend on how they respond to any treatments you may use for them. Certain side effects, such as keratitis and pink eye, may persist or reoccur even with treatment.

If you have questions or concerns about how long Dupixent’s side effects may last, talk with your doctor.

Will using Dupixent give you headaches or make you feel fatigued?

Headaches have been reported as a side effect in studies of Dupixent, but fatigue (low energy) has not. That’s not to say fatigue won’t happen with this drug. Headache and fatigue are common side effects many medications may cause. They’re also a common problem in people with long-term conditions.

If headaches or fatigue are bothering you during Dupixent treatment, talk with your doctor. They can look for the cause and recommend ways to manage them.

Can using Dupixent increase your risk of cancer?

No, that’s not likely. Studies haven’t found any increased risk of cancer in people who receive Dupixent.

There is an increased risk of cancer with certain immunosuppressant medications used to treat severe eczema or asthma. Immunosuppressants reduce certain functions of your immune system, which is your body’s defense against disease. These medications can reduce your body’s ability to find and kill cancerous cells.

But Dupixent doesn’t weaken your entire immune system. It only affects a couple of immune system proteins. So it’s unlikely to affect your body’s ability to find and destroy cancerous cells.

Learn more about some of the side effects Dupixent may cause.

Joint pain

Some people may have joint pain (also known as arthralgia) during treatment with Dupixent. But in studies, arthralgia was reported only in people who took Dupixent for rhinosinusitis with nasal polyps (swelling in the nasal passages and sinuses with nasal polyps). This side effect was not particularly common.

If you have joint pain from Dupixent treatment, talk with your doctor or pharmacist about ways to manage this. For example, some of the following remedies may help:

  • applying hot or cold packs to affected joints
  • getting gentle exercise, such as swimming
  • practicing relaxation techniques, such as meditation or breathing exercises

If you have joint pain that’s bothersome, ask your pharmacist to recommend an over-the-counter pain reliever. Examples include acetaminophen (Tylenol) and anti-inflammatory gels, such as diclofenac (Voltaren). However, if you have asthma, avoid taking oral anti-inflammatories such as ibuprofen (Advil).

Eye-related side effects

Dupixent commonly causes ocular (eye-related) side effects. These side effects can be mild or serious.

Mild eye-related side effects that have been reported with Dupixent include:

Serious eye-related side effects that have been reported with Dupixent include keratitis (inflammation of the cornea). If keratitis isn’t treated, it can damage your eyesight or cause other problems, such as corneal ulcers.

In studies, eye-related side effects were more common in people who took Dupixent for eczema than for other uses. Conjunctivitis was reported more often than other eye-related side effects.

Symptoms of eye-related side effects may include:

If you wear contact lenses or have any current eye problems, talk with your doctor before starting Dupixent treatment. They can advise whether Dupixent is right for you. They can also suggest ways to help avoid eye-related side effects.

During Dupixent treatment, see your doctor right away if you have eye-related symptoms or any new or worsening eye problems. Your doctor will check your eyes and recommend a suitable treatment, depending on the symptoms you have.

Eosinophilic conditions

Dupixent can sometimes increase the number of eosinophils in your blood. Eosinophils are a type of white blood cell.

If you have too many eosinophils (a condition called eosinophilia), this can sometimes cause inflammatory conditions. Examples of these include pneumonia and vasculitis (inflammation of blood vessels).

Although rare, in early studies of Dupixent, these conditions were reported in people who took the drug to treat asthma. The conditions may have been related to people taking a lower dosage of oral steroid medications as Dupixent eased their asthma symptoms. (“Oral” means taken by mouth.) But it’s not known for sure if these conditions were caused by Dupixent.

Symptoms of these eosinophilic conditions may include:

If you have symptoms of this side effect, see your doctor right away. Your doctor will look into the cause of your symptoms and may prescribe treatment if needed.

If you’re taking an oral steroid medication, do not reduce your dose or stop taking it unless your doctor recommends it.

Dupixent injection site reactions

You may have injection site reactions during Dupixent treatment. In studies, this was the most common side effect reported in people who received Dupixent for any condition. It occurred most often with the initial dose of the drug.

Injection site reactions may cause the following symptoms in the area where you have a Dupixent injection:

  • redness or change in skin color
  • pain
  • bruising
  • swelling
  • itching

Injection site reactions are usually mild and get better within a few days.

To help avoid injection site reactions, inject into a different area each time you give yourself a dose of Dupixent. This is called rotating injection sites. Make a note of the date and the site you use each time as a reminder.

Avoid injecting into areas of skin that are tender, bruised, damaged, or scarred. Do not rub the injection site after the injection.

If you have an injection site reaction that’s causing discomfort, it may help to apply a cold pack to the area. Contact your doctor if you have a reaction that’s severe or doesn’t get better.

Keeping track of side effects

During your Dupixent treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how a drug affects you. And your doctor can use this information to adjust your treatment plan if needed.

Dupixent can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Dupixent is a good treatment option for you.

Talk with your doctor about your health history before you start Dupixent treatment. Be sure to tell them if any of the following factors apply to you:

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.